The present invention relates to a variable-pitch propeller. More particularly this invention concerns such a propeller having a plurality of vanes rotatable on the propeller hub.
A variable-pitch propeller has a plurality of vanes each rotatable about a respective vane axis that extends radially of the rotation axis for the propeller hub. Such a propeller can be used in a compressor or fan, on a water-going vessel as the drive screw, or even on an aircraft. As the vanes are rotated so that the angles they form with the hub axis become smaller the fluid throughput increases and vice versa.
This variation in pitch is normally obtained by providing on each of the vanes an eccentric crank pin which is connected to an adjustment member that is displaceable along the hub axis. Complex linkages comprising pivotable crank arms or coulisse-guided slide-blocks are provided between each of these crank pins and the adjustment member so that a displacement of the adjustment member along the hub axis will pivot the vanes about the vane axes.
These known devices comprise many finely machined parts, usually require an increased hub length and cause difficulties during assembling and maintenance service.